python实现DES加密

下面是一个简单的Python代码实现DES加密：

from Crypto.Cipher import DES

def des_encrypt(key, plaintext):
    cipher = DES.new(key, DES.MODE_ECB)
    padded_plaintext = plaintext + ((8 - len(plaintext) % 8) * chr(8 - len(plaintext) % 8)).encode()
    ciphertext = cipher.encrypt(padded_plaintext)
    return ciphertext

key = b'abcdefgh'
plaintext = b'This is a plaintext message.'

ciphertext = des_encrypt(key, plaintext)
print(ciphertext)

其中，`key`是一个8字节的字符串，`plaintext`是待加密的明文。在函数中，首先使用Crypto库中的DES模块创建一个DES加密器，然后对明文进行填充以保证其长度为8的倍数，最后使用加密器对其进行加密。输出的`ciphertext`即为加密后的密文。

相关问题

python实现DES加密算法

DES是一种对称加密算法，Python中可以使用pycryptodome库来实现DES加密算法。以下是使用pycryptodome库实现DES加密算法的示例代码：

from Crypto.Cipher import DES

def des_encrypt(key, data):
    cipher = DES.new(key.encode(), DES.MODE_ECB)
    pad_len = 8 - len(data) % 8
    padding = bytes([pad_len] * pad_len)
    data += padding
    ciphertext = cipher.encrypt(data)
    return ciphertext

key = '12345678' # 密钥必须为8个字符
data = b'hello world' # 待加密的数据必须是bytes类型
ciphertext = des_encrypt(key, data)
print(ciphertext.hex())

在该示例代码中，我们使用了DES.MODE_ECB模式进行加密，即ECB模式。同时，我们还使用了PKCS#5的填充方式对数据进行了填充。如果你想要使用其他的填充方式，可以在padding变量处做出修改。

如果你需要对加密后的密文进行解密，可以使用如下代码：

from Crypto.Cipher import DES

def des_decrypt(key, ciphertext):
    cipher = DES.new(key.encode(), DES.MODE_ECB)
    data = cipher.decrypt(ciphertext)
    pad_len = data[-1]
    return data[:-pad_len]

key = '12345678' # 密钥必须为8个字符
ciphertext = bytes.fromhex('1a8c1d5e3a9c9dcb') # 加密后得到的密文必须是bytes类型
data = des_decrypt(key, ciphertext)
print(data.decode())

在该示例代码中，我们使用了与加密时相同的密钥和填充方式进行解密。需要注意的是，解密后得到的数据可能存在填充内容，需要根据填充长度进行截取。

python实现des加密算法

以下是Python实现DES加密算法的示例代码：

from typing import List

# 初始置换表IP
IP_TABLE = [58, 50, 42, 34, 26, 18, 10, 2,
            60, 52, 44, 36, 28, 20, 12, 4,
            62, 54, 46, 38, 30, 22, 14, 6,
            64, 56, 48, 40, 32, 24, 16, 8,
            57, 49, 41, 33, 25, 17, 9, 1,
            59, 51, 43, 35, 27, 19, 11, 3,
            61, 53, 45, 37, 29, 21, 13, 5,
            63, 55, 47, 39, 31, 23, 15, 7]

# 逆初始置换表IP^-1
IP_INV_TABLE = [40, 8, 48, 16, 56, 24, 64, 32,
                39, 7, 47, 15, 55, 23, 63, 31,
                38, 6, 46, 14, 54, 22, 62, 30,
                37, 5, 45, 13, 53, 21, 61, 29,
                36, 4, 44, 12, 52, 20, 60, 28,
                35, 3, 43, 11, 51, 19, 59, 27,
                34, 2, 42, 10, 50, 18, 58, 26,
                33, 1, 41, 9, 49, 17, 57, 25]

# 扩展置换表E
E_TABLE = [32, 1, 2, 3, 4, 5,
           4, 5, 6, 7, 8, 9,
           8, 9, 10, 11, 12, 13,
           12, 13, 14, 15, 16, 17,
           16, 17, 18, 19, 20, 21,
           20, 21, 22, 23, 24, 25,
           24, 25, 26, 27, 28, 29,
           28, 29, 30, 31, 32, 1]

# 置换函数P
P_TABLE = [16, 7, 20, 21, 29, 12, 28, 17,
           1, 15, 23, 26, 5, 18, 31, 10,
           2, 8, 24, 14, 32, 27, 3, 9,
           19, 13, 30, 6, 22, 11, 4, 25]

# S盒
S_BOX = [
    # S1
    [
        [14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7],
        [0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8],
        [4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0],
        [15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13]
    ],
    # S2
    [
        [15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10],
        [3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5],
        [0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15],
        [13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9]
    ],
    # S3
    [
        [10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8],
        [13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1],
        [13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7],
        [1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12]
    ],
    # S4
    [
        [7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15],
        [13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9],
        [10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4],
        [3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14]
    ],
    # S5
    [
        [2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9],
        [14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6],
        [4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14],
        [11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3]
    ],
    # S6
    [
        [12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11],
        [10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8],
        [9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6],
        [4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13]
    ],
    # S7
    [
        [4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1],
        [13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6],
        [1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2],
        [6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12]
    ],
    # S8
    [
        [13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7],
        [1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2],
        [7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8],
        [2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11]
    ]
]

# 置换选择1
PC1_TABLE = [57, 49, 41, 33, 25, 17, 9,
             1, 58, 50, 42, 34, 26, 18,
             10, 2, 59, 51, 43, 35, 27,
             19, 11, 3, 60, 52, 44, 36,
             63, 55, 47, 39, 31, 23, 15,
             7, 62, 54, 46, 38, 30, 22,
             14, 6, 61, 53, 45, 37, 29,
             21, 13, 5, 28, 20, 12, 4]

# 置换选择2
PC2_TABLE = [14, 17, 11, 24, 1, 5,
             3, 28, 15, 6, 21, 10,
             23, 19, 12, 4, 26, 8,
             16, 7, 27, 20, 13, 2,
             41, 52, 31, 37, 47, 55,
             30, 40, 51, 45, 33, 48,
             44, 49, 39, 56, 34, 53,
             46, 42, 50, 36, 29, 32]

# 左移位数表
SHIFT_TABLE = [1, 1, 2, 2, 2, 2, 2, 2,
               1, 2, 2, 2, 2, 2, 2,